Thailand and Cambodia Begin UNCLOS Maritime Dispute Talks

The Government of Cambodia and the Government of Thailand began a compulsory conciliation process in Singapore on September 14, 2026, to resolve a long-standing maritime dispute in the Gulf of Thailand. The conflict centers on an overlapping claim to approximately 26,000 to 27,000 square kilometers of seabed containing an estimated 12 trillion cubic feet of natural gas and oil valued at $300 billion.

Cambodia triggered the United Nations Convention on the Law of the Sea (UNCLOS) process after Thailand unilaterally cancelled a 2001 memorandum of understanding, known as MoU 44, in May 2026. While Thai Prime Minister Anutin Charnvirakul denied the withdrawal was linked to deadly 2025 border clashes, Cambodian Prime Minister Hun Manet stated the legal action is necessary to protect national sovereignty.

During opening statements on September 15, Cambodian Foreign Minister Prak Sokhonn proposed either a single maritime boundary treaty or an agreement for the joint development and equitable sharing of resources. Thai Foreign Minister Sihasak Phuangketkeow rejected this approach, insisting the proceedings must focus exclusively on boundary delimitation before any other discussions. He argued that Thailand scrapped the previous framework to jumpstart stalled talks.

A five-member commission chaired by Australian diplomat Katrina Cooper is mediating the dispute at the Permanent Court of Arbitration. The panel will conduct a 12-month review process before issuing a non-binding report with proposed terms for a settlement.